Sustainable use of recycled water for horticultural irrigation on the Northern Adelaide Plains

105 Pages·2004·2.87 MB·English

Sustainable use of
recycled water for
horticultural irrigation
on the Northern
Adelaide Plains

Dr Daryl Stevens
The University of Adelaide

Project Number: VG97081
VG97081

This report is published by Horticulture Australia Ltd to
pass on information concerning horticultural research
and development undertaken for the vegetable
industry.

The research contained in this report was funded by
Horticulture Australia Ltd with the financial support of
the vegetable and potato industries.

All expressions of opinion are not to be regarded as
expressing the opinion of Horticulture Australia Ltd or
any authority of the Australian Government.

The Company and the Australian Government accept
no responsibility for any of the opinions or the
accuracy of the information contained in this report
and readers should rely upon their own enquiries in
making decisions concerning their own interests.

ISBN 0 7341 0857 5

Published and distributed by:
Horticultural Australia Ltd
Level 1
50 Carrington Street
Sydney NSW 2000
Telephone: [phone]
Fax: [phone]
E-Mail: [email protected]

© Copyright 2004
HAL Project - VG 97081

Sustainable use of reclaimed water for
Horticultural Irrigation on the
Northern Adelaide Plains

FINAL REPORT

March 2004

Dr Daryl Stevens et al
University of Adelaide, CSIRO Land and Water &
ARRIS Pty Ltd
Project leader: Dr Daryl Stevens
Research Scientist
ARRIS Pty Ltd, University of Adelaide &
CSIRO Land & Water.
Waite Road
URRBRAE SA 5064

Phone: [phone]
Mobile: [phone]
Email: [email protected]

Key personnel: Michelle Smart, Jim Kelly, Dr Mike McLaughlin, Dr
Nabil Gerges, Dr Gary Owens, Marti van der Wielen,
Dr Pichu Rengasamy and Norbert Myer.

The purpose of this report is to communicate the final outcomes and
impacts to the Horticulture and reclaimed water industry of the HAL
project VG 97081 including research, communication resources and
publications. We wish to acknowledge and thank our primary funding
source, Horticulture Australia Limited, and our additional funding
sources - Northern Adelaide and Barossa Catchment Water Management
Board and Water Reticulation Services Virginia Adelaide and Barossa
Catchment Water Management Board which supported add-on projects

Any recommendations contained in this publication do not necessarily represent
current Horticulture Australia policy. No person should act on the basis of the
contents of this publication, whether as to matters of fact or opinion or other
content, without first obtaining specific, independent professional advice in respect
of the matters set out in this publication.

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CONTENTS

1 Abbreviations_________________________________________________5
2 Media Summary ______________________________________________6
3 Technical summary____________________________________________6
4 Introduction__________________________________________________8
5 Methods____________________________________________________10
5.1 Soils Research_______________________________________________10
5.1.1 Historical comparison – Effect of water type on key soil
properties.______________________________________________10
5.1.2 Glasshouse study – Effect of irrigation water and practice on
cadmium uptake by lettuce. ________________________________12
5.1.3 Field experiment – Assessment of soil additives on managing
sodicity.________________________________________________14
5.2 Produce quality _____________________________________________17
5.2.1 Heavy metals in vegetables on the NAP – a baseline study________18
5.2.2 Heavy metals in produce grown in field trials __________________18
5.2.3 Microbial or algal contamination of vegetables by irrigation with
reclaimed water__________________________________________19
5.3 Water & Nutrient Mass balance________________________________21
5.3.1 Water quality____________________________________________21
5.3.2 Nutrient balances ________________________________________21
5.4 Groundwater _______________________________________________21
5.4.1 Groundwater monitoring___________________________________21
5.4.2 District water balances ____________________________________26
6 Results and related discussion __________________________________33
6.1 Soils Research_______________________________________________33
6.1.1 Historical comparison – Effect of water type on key soil
properties.______________________________________________33
6.1.2 Electrical conductivity ____________________________________37
6.1.3 Glasshouse study – Effect of irrigation water and practice on
cadmium uptake by lettuce. ________________________________48
6.1.4 Field experiment – Assessment of soil additives on managing
sodicity.________________________________________________49
6.2 Produce quality _____________________________________________63
6.2.1 Heavy metals in vegetables on the NAP – a baseline study________63
6.2.2 Heavy metals in produce grown in field trials __________________64
6.2.3 Microbial or algal contamination of vegetables by irrigation with
reclaimed water__________________________________________64
6.3 Water & Nutrient Mass balance________________________________68
6.3.1 Water quality____________________________________________68
6.3.2 Nutrient balances ________________________________________68
6.4 Groundwater _______________________________________________69
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6.4.1 Groundwater monitoring___________________________________69
6.4.2 District water balances ____________________________________77
7 Discussion__________________________________________________81
7.1 Soils_______________________________________________________81
7.1.1 Historical comparison - effect of water type on soil quality________81
7.1.2 Field trials soil amendments________________________________81
7.1.3 Glasshouse study – Effect of irrigation water and practice on
cadmium uptake by lettuce. ________________________________82
7.2 Produce quality _____________________________________________82
7.2.1 Heavy metals in vegetables on the NAP – a baseline study________82
7.2.2 Heavy metals in produce grown in field trials __________________82
7.2.3 Microbial or algal contamination of vegetables by irrigation with
reclaimed water__________________________________________82
7.3 Groundwater _______________________________________________83
7.3.1 Groundwater modelling ___________________________________83
7.3.2 District water balance_____________________________________83
7.4 The specific outcomes of the research project_____________________84
7.4.1 Develop a management strategy for irrigating horticultural crops
with reclaimed water. _____________________________________84
7.4.2 Produce a public awareness brochure on the benefits and
limitations of irrigating with reclaimed water to ensure its
sustainable use __________________________________________84
7.4.3 Produce a grower manual for use of reclaimed water in
horticulture on the Northern Adelaide Plains. Identifying soil
types, land capabilities and relevant management techniques for
growing particular horticultural crops with reclaimed water _______85
7.4.4 Establish research and development priorities with respect to the
management of reclaimed water to ensure productivity and
quality of produce. _______________________________________85
8 Technology transfer __________________________________________86
8.1 Award _____________________________________________________86
8.2 Growers and industry ________________________________________86
8.2.1 Workshops _____________________________________________86
8.2.2 Field Days______________________________________________86
8.2.3 Reports ________________________________________________86
8.2.4 Presentations____________________________________________86
8.2.5 Promotional and education material__________________________88
8.2.6 Study tours _____________________________________________88
8.2.7 Grower Manual – Sustainable use of reclaimed water on the
Northern Adelaide Plains __________________________________88
8.2.8 Community service_______________________________________89
8.3 Scientific ___________________________________________________91
8.3.1 Papers _________________________________________________91
8.3.2 Presentations____________________________________________92
8.3.3 Reference Manual - Sustainable use of reclaimed water on the
Northern Adelaide Plains __________________________________92
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8.3.4 Textbook - Growing food crops with reclaimed wastewater: An
Australian Perspective.____________________________________92
8.3.5 Advisory roles___________________________________________92
8.3.6 Scientific workshops______________________________________93
8.3.7 Field trip - Australian Water Association Water Recycling
Forum _________________________________________________93
8.4 Press Articles._______________________________________________93
8.4.1 Television Media Segments ________________________________94
8.4.2 Horticulture Australia Promotional Videos ____________________94
9 Recommendations - scientific and industry________________________94
9.1 Further Research Identified___________________________________94
9.1.1 Hydroponic production using reclaimed water. _________________94
9.1.2 Surface water table on the NAP _____________________________95
9.1.3 Coordinator of reclaimed water development in horticulture_______95
9.1.4 Irrigation Development Officer _____________________________95
9.2 Study Tour _________________________________________________95
10 Research projects developed from recommendations.________________97
10.1 Sustainable Salinity and Water Management on the Northern Adelaide
Plains. Stage 1 – Identification of actions to provide a sustainable water
balance and prevent salinity damage____________________________97
10.2 Drainage Fluxes to the Water Table Beneath Irrigated Crops on the
Northern Adelaide Plains: Comparison of Existing and Alternative
Irrigation Management Systems _______________________________97
10.3 Coordinator of Reclaimed Water Development in Horticulture. _____97
10.4 Reclaimed water use in Australian Horticulture. Developing an
environmental and economically sustainable approach for Australia._97
11 Acknowledgments____________________________________________98
12 Bibliography of literature cited__________________________________98
13 Appendix of all publications related to the project _________________103

1 Abbreviations
NAP – Northern Adelaide Plains
RCW – reclaimed water
CARW – Class A Reclaimed Water
EC – Electrical Conductivity
SAR – Sodium Adsorption Ratio
NABCWMB – Northern Adelaide Plains and Barossa Catchment Water
Management Board

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2 Media Summary
Project VG79081: Sustainable use of reclaimed water for Horticultural Irrigation
on the Northern Adelaide Plains
This Horticultural Australia Limited project has played a pivotal role in helping the
ground-breaking development of a sustainable reclaimed water scheme in the Virginia
Triangle, South Australia (One of the largest Class A reclamation and reuse schemes
in the world). It has secured a safe, environmentally friendly, and guaranteed water
source for a diverse range of horticulture in SA. Australia now has some of the world
leaders in water reclamation and reuse industry. Recently the knowledge acquired
during this project has been captured in a new project funded by Horticultural
Australia Limited, that will help coordinate reclaimed water development in
horticulture across Australia; maximising the potential benefits to Australian
horticulture.

3 Technical summary
In 1998, for the first time in Australia, water reclaimed from sewage wastewater
treatment plants was going to be used for the production of vegetables and a range of
other horticultural products (eg. almonds, grapevines). The SA Department of
Human Services completed extensive research and verification programs to ensure the
treatment process was capable of guaranteeing a supply of Class A water to the
Northern Adelaide Plain horticultural precinct. They set standards for this Class A
water would ensure any health risks were extremely low (eg. effectively zero).
However, growers were still concerned about the sustainability of irrigation with
reclaimed water from an agronomic and environmental aspect. This project aimed to
ensure the practice would be sustainable and, if not, assess if management techniques
could be adopted to cope with the different water sources. The broad objectives of
this research project were to:
• monitor the effects of reclaimed water on soil fertility and degradation of soil
physical properties in the NAP;
• determine any short or long-term detrimental/beneficial effects on soil fertility
due to the use of reclaimed water; and
• develop and communicate management techniques appropriate for the soils on
the NAP to ensure that use of reclaimed water will increase productivity and
economic return, while not degrading the environment.
Research activities identified and monitored key indicators for sustainability. This
included soil boron concentrations, salinity and sodium adsorption ratios. A range of
extension projects culminated in the development of user manual for growers, a text
book on reclaimed water use in Australian agriculture, and the maintenance of the
quality of produce grown with reclaimed water.
Specific outcomes from the research project have been:
• Awareness that SAR of the irrigation water may need to be decreased and/or
appropriate farming methods developed and practised with the use of RCW to
protect these soils for future horticultural activities (Stevens et al 2003).
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• A low cost soil test, using a simple 1:5 soil:water extract was compared to
accepted soil extracts (for assessing detrimental physico-chemical soil
changes) and has been proposed as a grower management tool to assist in
monitoring the physico-chemical changes (boron, salinity and sodicity) of the
NAP soils(see Stevens et al 2003).
• Recommendations to manage the regional water table.
• A grower awareness of problems with algae when using reclaimed water and
methods to manage potential issues.
• Confirmation that produce grown with reclaimed water is as safe as any
produce grown with any other water source. Improving grower confidence in
reclaimed water.
• Production of a grower manual for use of reclaimed water in horticulture on
the Northern Adelaide Plains. Identifying soil types, land capabilities and
relevant management techniques for growing particular horticultural crops
with reclaimed water from the Bolivar Wastewater Treatment Plant.
• Extensive communication to the water industry across Australia regarding the
possibilities of developing reclaimed water schemes with a range of
horticultural commodities.
• Exposure of the Australian general public, through ABC’s Landline program,
to positive stories involving horticultural use of reclaimed water in Australia,
United States of America and Israel.

Future work suggested includes:
• Hydroponic or soil-less culture production using reclaimed water
• Management of the surface water-table on the Northern Adelaide Plains
• A coordinator of reclaimed water development in Australian Horticulture
• Irrigation development officers for some horticultural areas

Research project which have developed from these recommends are:
• Sustainable Salinity and Water Management on the Northern Adelaide Plains.
Stage 1 – Identification of actions to provide a sustainable water balance and
prevent salinity damage. Funded (2002) by the National Action Plans for
Salinity and the Northern Adelaide and Barossa Catchment Management
Board
• Drainage Fluxes to the Water Table beneath Irrigated Crops on the Northern
Adelaide Plains: Comparison of Existing and Alternative Irrigation
Management Systems. Funded (2003) by the Northern Adelaide Plains and
Barossa Catchment Water Management Board (NABCWMB).
• Coordinator Reclaimed Water Development Horticulture. Funded by
Horticulture Australia Limited (2003), with a voluntary contribution from the
horticultural and water industries, and state government departments.
• Reclaimed water use in Australian Horticulture. Developing an environmental
and economically sustainable approach for Australia. Funded by Land and
Water Australia (2003).

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4 Introduction
While the earth’s population grows, there is increasing demand on fresh water
supplies, for a variety of needs. Now, and in the future, water resources will need to
be better managed. One option available for better management of water is
reclamation of sewage effluent (reclaimed water). Already, reclaimed water is often
used for irrigating parklands and golf courses, there are also some domestic non-
potable reuse applications (Law 1996; Mujeriego et al 1996; Shelef, Azov 1996).
Planned water reuse requires adequate treatment to meet the quality requirements of
the intended reuse. In the near future, agricultural and urban irrigation will play an
important role in water reuse, especially in dry climates (Bouwer 1994).
A good supply of underground water for irrigation has developed the Virginia area of
the Northern Adelaide Plains (NAP) into a major producer of horticultural crops in
South Australia. However, the long-term supply of this water was threatened. Total
pumping volumes from aquifers have been estimated to be much greater than the total
recharge (Anon 1995).
Reclaimed water may be a relatively simple solution to water scarcity problems.
However, it could have potential adverse long-term effects on sustainable use of
agricultural soils and ground water quality. Several recent studies, involving the
application of reclaimed water, have shown declines in soil fertility related to
degradation of soil structure and increases in salinity and sodicity. Others issues
which have been flagged by these studies are: increasing soil boron levels;
contamination of ground waters; bacterial and pathogenic contamination of produce;
clogging of irrigation equipment and enhanced transport of some pesticides
(Wienhold, Trooien 1995; Curtin et al 1995; Myers et al 1995; Armon et al 1994;
Muszkat et al 1993; Juanico et al 1995; Graber et al 1995). The majority of these
studies have been completed on soils with different hydrological and physico-
chemical properties to soils of the NAP and many used for intense horticulture
throughout Australia.
From the limited data available, the short and long-term detrimental effects of
reclaimed water use in the NAP are unknown. Possible management techniques to
overcome potentially detrimental effects must be explored to ensure the short-term
gains of a guaranteed water supply are not offset by the deterioration of soil fertility.
Changes in irrigation management may also be required to ensure reclaimed water,
which has much higher salinity than the aquifer water currently used, is used
correctly.
At the beginning of the project there was no such research being conducted on the
NAP. With the imminent release of reclaimed water for irrigation purposes, research
in this area was vital to ensure best management practices were adopted for the
district and to verify that large-scale reclamation schemes were viable for the
horticultural industry in Australia. Instigated correctly, reclaimed water used for
horticultural purposes on the NAP could set the example for similar horticultural uses
across Australia and provide a sustainable, guaranteed, renewable water resource for
the horticultural industry, whilst relieving pressures on potable water resources. If
successful, such a scheme could also provide the horticultural industry with the
confidence to embrace this renewable water resource for the foreseeable future;
providing a valuable resource for a range of horticultural enterprises.

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